Shoreline displacement in the Belomorsk area, NW Russia during the Younger Dryas Stadial

Abstract

A total of six small basins were cored to determine the shoreline displacement of the Belomorsk area, NW Russia during the last deglaciation. Conventional shoreline displacement methods were applied where the isolation contacts of the sediment cores from lakes at different altitudes were determined using lithological and diatom taxa changes. The isolation contacts were subsequently dated using the 14C AMS-method. The results show that the area around the cored basins formed part of an extensive ice lake that existed in the White Sea Basin prior to 12,000 cal. yr BP. Dating, together with lithostratigraphical and diatom results, indicate that the isolation of the lakes between 72 and 134 m above the present sea level occurred at 12,000 cal. yr BP and the relative water level in the White Sea Basin dropped at least 62 m within a maximum of 300 years. It is estimated that at least 50–55 m of the relative water-level fall was caused by a sudden drainage of the ice-lake waters into the Barents Sea via the Gorlo Strait and 7–12 m of the water-level decline was caused by glacioisostatic uplift. Preliminary calculations suggest that the total volume of water that burst into the Barents Sea was c. 3000 km3. This, together with that of c. 7000 km3 of water which drained into the North Atlantic as the result of the Baltic Ice Lake drop around 11,600 cal. yr BP, must have affected the behaviour of the eastern flank of the Scandinavian Ice Sheet and had a cooling effect on local climate.